The embodiment relates to an ingot pressing apparatus and an ingot slicing apparatus including the same.
Generally, in a wafer manufacturing process, a slicing process is performed to slice an ingot grown into a wafer shape during a crystal growth process, and a wire sawing process is a typical slicing process.
Through the wire sawing process, a degree of planarization of a wafer can be improved, and more specifically, a degree of warpage (warping and bowing) of the wafer can be controlled.
The wire sawing process is a process in which an ingot comes into contact with a wire and the ingot is sliced to have a plurality of wafer forms.
A wire sawing apparatus used in the wire sawing process is provided with a plate configured to support an ingot and a roller on which a wire is wound.
Accordingly, in the wire sawing process, an ingot is sliced to have a wafer form by the plate supporting the ingot being relatively moved in a direction of the wire wound on the roller.
During the slicing process of an ingot through wire sawing, a quality of the sliced wafers can be determined by a thermal expansion of the ingot itself, a slurry supplied to the wire during the slicing process, a spindle for rotating the roller which the wire is wound on so that the wire reciprocates, and thermal expansion of the plate holding the ingot.
FIG. 1 is a view illustrating a wire sawing apparatus according to a conventional art, FIG. 2 is a view illustrating an ingot slicing shape according to the conventional art.
A wire sawing apparatus 101 according to the conventional art includes a wire 102 for slicing an ingot, a roller 103 (a wire guide) on which the wire 102 is wound, a tension applying unit 104 for applying tension to the wire 102, an ingot transfer unit 105 which moves the ingot to be sliced, a slurry supply unit 106 which supplies slurry while the ingot is being sliced.
The wire 102 is continuously fed from a wire reel 107, passes through the tension applying unit 104 which includes a powder clutch (a constant torque motor 109), a dancer roller (a dead weight), etc., wherein a traverser 108 is disposed between the wire reel 107 and the tension applying unit 104, and is wound on the roller 103. After the wire 102 is wound on the roller 103 about 300 to 400 times, the wire 102 passes through a tension applying unit 104′ and is wound on a wire reel 107′.
Further, the grooved roller 103 is a roller in which a polyurethane resin is applied around a steel cylinder and grooves are formed with a constant pitch on a surface thereof, and the wound wire 102 can be driven in reciprocating directions in a cycle determined by a driving motor 110.
Further, while the ingot is being sliced, the ingot can be moved toward the wire 102 wound on the roller 103 by the ingot transfer unit 105.
Further, a nozzle 115 may be installed near the wire 102 wound on the roller 103 and may supply a slurry from a slurry tank 116 onto the roller 103 and the wire 102 while the ingot is being sliced. Furthermore, a slurry chiller 117 may be connected to the slurry tank 116 so that a temperature of the supplied slurry may be controlled.
By using the wire sawing apparatus 101, suitable tension is applied to the wire 102 using the tension applying unit 104, and the wire 102 is moved in the reciprocating directions to slice the ingot by the driving motor 110.
While the slicing process is being performed, expansion of a frame supporting the ingot, the ingot, and a roller portion occurs due to slicing heat. Since sides of a seed and a tail of the ingot being sliced are deformed due to thermal expansion that occurs at each of the above portions, there are problems in that a degree of planarization of a wafer is lowered and a shape of a sliced surface of the wafer is not uniform.